St. Louis University begins test of new vaccines for smallpox

Wednesday, August 20, 2003

ST. LOUIS -- St. Louis University researchers began a new smallpox vaccine trial Tuesday fueled, in part, by interest in providing protection against a potential bioterrorism attack.

The last case of smallpox in the United States was in 1949, but after the Sept. 11, 2001, attacks, the government stepped up work to keep the vaccine on hand in case the disease is reintroduced in an act of terrorism.

Existing smallpox vaccines cause rare but potentially severe side effects. Scientists said that out of every 1 million people being vaccinated for the first time, between 14 and 52 will face serious, life-threatening reactions, and one or two will die.

The new vaccines are being researched because they can be produced in a controlled laboratory environment using cell cultures. The old method needed cows for production.

The hope is that a new vaccine would be safer. "We certainly would hope that could be the case," said the lead investigator, Sharon Frey.

Seeking volunteers

The university is seeking 90 adult volunteers for the study. Thirty will receive one new vaccine developed by Cambridge, Mass.-based Acambis Inc.; 30 will receive another new Acambis vaccine, and 30 will receive Dryvax, the same smallpox vaccine administered to the public when smallpox vaccinations were routine.

However, the Dryvax in the trial will use a different solution to change the vaccine from its dry state -- the way it's stored -- to its liquid state, the way it's administered.

"We'll be comparing the three vaccines to each other to determine safety and the body's response to the vaccine," said Frey. "A need was thought to exist because of a concern of bioterrorism."

The United States currently has an effective supply of smallpox vaccine, but it was produced and stored in the 1980s.

Efforts to update the way the smallpox vaccine is produced were being worked on before Sept. 11, said Carole Heilman, who runs the Division of Microbiology and Infectious Diseases for the National Institute of Allergy and Infectious Diseases.

But, she said, efforts increased following the attacks. "It's still very high on the president's list of things to do," she said.

Other smallpox vaccines are being investigated, including types that could be administered to people who cannot tolerate existing smallpox vaccines due to other health conditions.

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